Local and Landscape Effects on Carrion-Associated Rove Beetle (Coleoptera: Staphylinidae) Communities in German Forests

Intensification of anthropogenic land use is a major threat to biodiversity and thus to essential ecosystem services provided by insects. Rove beetles (Coleoptera: Staphylinidae), which react sensitively to habitat changes, are species-rich colonizers of vertebrate cadavers and contribute to the important ecosystem service of carrion decomposition. The unveiling of anthropogenic and environmental drivers that modify carrion-associated rove beetle communities should improve our understanding of the plasticity of cadaver decay. We report the presence of 80 rove beetle species on 65 decomposing piglet cadavers at forest sites characterized by a gradient of management intensity across three geographic regions in Germany. Local and landscape drivers were revealed that shape beetle abundance, diversity, and community composition. Forest management and regions affect rove beetle abundance, whereas diversity is influenced by local habitat parameters (soil pH, litter cover) and regions. The community composition of rove beetles changes with management intensification by promoting generalist species. Regarding single species, Philonthus decorus and Anotylus mutator are linked to unmanaged forests and Ontholestes tessellatus to highly used forest stands. The spatial information provided about carrion-associated rove beetle communities in German forests is not only of carrion-ecological but also of forensic entomological interest

The attraction of the dung beetle anoplotrupes stercorosus (coleoptera: geotrupidae) to volatiles from vertebrate cadavers

During decomposition, vertebrate carrion emits volatile organic compounds to which insects and other scavengers are attracted. We have previously found that the dung beetle, Anoplotrupes stercorosus, is the most common dung beetle found on vertebrate cadavers. Our aim in this study was to identify volatile key compounds emitted from carrion and used by A. stercorosus to locate this nutritive resource. By collecting cadaveric volatiles and performing electroantennographic detection, we tested which compounds A. stercorosus perceived in the post-bloating decomposition stage. Receptors in the antennae of A. stercorosus responded to 24 volatiles in odor bouquets from post-bloating decay. Subsequently, we produced a synthetic cadaver odor bouquet consisting of six compounds (benzaldehyde, DMTS, 3-octanone, 6-methyl-5-hepten-2-ol, nonanal, dodecane) perceived by the beetles and used various blends to attract A. stercorosus in German forests. In field assays, these beetles were attracted to a blend of DMTS, 3-octanone, and benzaldehyde. Generalist feeding behavior might lead to the super-dominant occurrence of A. stercorosus in temperate European forests and have a potentially large impact on the exploitation and rapid turnover of temporally limited resources such as vertebrate cadavers

Linking bacteria, volatiles and insects on carrion: the role of temporal and spatial factors regulating inter-kingdom communication via volatiles

Multi-kingdom community complexity and the chemically mediated dynamics between bacteria and insects have recently received increased attention in carrion research. However, the strength of these inter-kingdom interactions and the factors that regulate them are poorly studied. We used 75 piglet cadavers across three forest regions to survey the relationship between three actors (epinecrotic bacteria, volatile organic compounds (VOCs) and flies) during the first 4 days of decomposition and the factors that regulate this interdependence. The results showed a dynamic bacterial change during decomposition (temperature–time index) and across the forest management gradient, but not between regions. Similarly, VOC emission was dynamic across a temperature–time index and the forest management gradient but did not differ between regions. However, fly occurrence was dynamic across both space and time. The strong interdependence between the three actors was mainly regulated by the temperature–time index and the study regions, thereby revealing regulation at temporal and spatial scales. Additionally, the actor interdependence was stable across a gradient of forest management intensity. By combining different actors of decomposition, we have expanded our knowledge of the holistic mechanisms regulating carrion community dynamics and inter-kingdom interactions, an important precondition for better describing food web dynamics and entire ecosystem functions

Eleven years’ data of grassland management in Germany

The 150 grassland plots were located in three study regions in Germany, 50 in eachregion. The dataset describes the yearly grassland management for each grassland plotusing 116 variables.General information includes plot identifier, study region and survey year. Additionally,grassland plot characteristics describe the presence and starting year of drainage andwhether arable farming had taken place 25 years before our assessment, i.e. between1981 and 2006. In each year, the size of the management unit is given which, in somecases, changed slightly across years.Mowing, grazing and fertilisation were systematically surveyed:Mowing is characterised by mowing frequency (i.e. number of cuts per year), dates ofcutting and different technical variables, such as type of machine used or usage ofconditioner.For grazing, the livestock species and age (e.g. cattle, horse, sheep), the number ofanimals, stocking density per hectare and total duration of grazing were recorded. As aderived variable, the mean grazing intensity was then calculated by multiplying thelivestock units with the duration of grazing per hectare [LSU days/ha]. Different grazingperiods during a year, partly involving different herds, were summed up to an annualgrazing intensity for each grassland.For fertilisation, information on the type and amount of different types of fertilisers wasrecorded separately for mineral and organic fertilisers, such as solid farmland manure,slurry and mash from a bioethanol factory. Our fertilisation measures neglect dung droppedby livestock during grazing. For each type of fertiliser, we calculated its total nitrogencontent, derived from chemical analyses by the producer or agricultural guidelinesAll three management types, mowing, fertilisation and grazing, were used to calculate acombined land use intensity index (LUI) which is frequently used to define a measure forthe land use intensity. Here, fertilisation is expressed as total nitrogen per hectare [kg N/ha], but does not consider potassium and phosphorus.Information on additional management practices in grasslands was also recorded includinglevelling, to tear-up matted grass covers, rolling, to remove surface irregularities, seedaddition, to close gaps in the sward.New informationInvestigating the relationship between human land use and biodiversity is important tounderstand if and how humans affect it through the way they manage the land and todevelop sustainable land use strategies. Quantifying land use (the ‘X’ in such graphs) canbe difficult as humans manage land using a multitude of actions, all of which may affectbiodiversity, yet most studies use rather simple measures of land use, for example, bycreating land use categories such as conventional vs. organic agriculture. Here, we providedetailed data on grassland management to allow for detailed analyses and thedevelopment of land use theory. The raw data have already been used for > 100 papers onthe effect of management on biodiversity (e.g. Manning et al. 2015)